The present invention relates to a mixed reality presentation apparatus and control method thereof, and in particular, to a mixed reality presentation apparatus and control method thereof which can allow for presentation of a mixed reality by superimposing a virtual space image on a physical space where tone and brightness may vary largely.
Recently, some systems or man-machine interfaces which use a mixed reality (MR) have been proposed. The MR is a technology for presenting a merged image of a virtual space generated by a computer and the physical space visually identified by an observer or taken in proximity to the observer""s viewpoint to mutually complement and augment the information on both spaces.
Among these systems which use the MR (MR systems), attention is focused on a system which superimposes and displays texts as virtual objects, additional information such as wire frames, and computer graphics (CG) objects on the physical space and this system is applied to information presentation to the observer or visual simulation.
Researches have been made to implement such an MR system outdoors and one of them is disclosed in a publication entitled xe2x80x9cA Touring Machine: Prototyping 3D Mobile Augmented Reality Systems for Exploring the Urban Environmentxe2x80x9d by Steven Feiner, Blair MacIntre, Tobias Hollerer, and Anthony Webster, Personal Technologies, vol. 1, no. 4, pp. 208-217, 1997.
The MR system disclosed in this publication is a system for guiding the observer throughout the premise of a university and displays on a head mounted display (HMD) of optical see-through type worn by the observer some guide information (such as campus names) generated based on the observer""s viewpoint position and orientation acquired through a global positioning system (GPS), a inclinometer, and a magnetometer. Thus, the observer can visually identify, for example, a campus existing on the physical space and a campus name displayed on the display in proper alignment therewith simultaneously and can receive the guide information in real time while walking through the premise.
However, when the MR system is used outdoors, the environmental conditions are largely different from those for indoor use and vary to a larger extent, which may create unique problems. Namely, since the outdoor environment is generally brighter than the indoor environment, it may be difficult for the observer to visually identify virtual objects, in particular, fine-line objects such as text information or wire frame information if the tone difference between these objects and the background real object is small.
In addition, as the observer moves, the tone, brightness, and lighting conditions of the physical space visually identified by the observer will vary within a very large range and thus, it is difficult to previously determine display colors such that the tone difference may be sufficiently large. Moreover, even if the observer does not move, the tone, brightness, and lighting conditions of the physical space may vary depending on date and time as well as weather conditions, which will create the same problems.
Similarly, when a CG object such as a sufficiently wide building is displayed as if it exists in the physical space, the virtual CG object cannot be merged into the physical space to make the observer feel disharmony if the MR system is used outdoors and the tone difference between the object and the background physical space is very large.
The problem that the visibility of the virtual object is deteriorated to make the observer feel disharmony depending on the tone and brightness of the physical space is very remarkable especially when the MR system is used outdoors but that problem may be caused by some change in lighting conditions, for example, due to the influence of sunlight even when the MR system is used indoors.
The present invention has been achieved in light of the above-mentioned disadvantages of the prior art and it is an object of the present invention to provide a mixed reality presentation apparatus and control method thereof which can allow for suitable display of a virtual object depending on the tone, brightness, and lighting conditions of the physical space on which the virtual object is superimposed and displayed.
According to an aspect of the present invention, a mixed reality presentation apparatus for presenting a mixed reality to an observer by superimposing a virtual space image composed of a virtual object image on a physical space or an image thereof visually identified by the observer and presenting the virtual space image to the observer is provided, wherein the apparatus includes: tone detection means for detecting a tone of a predetermined region in the physical space or the image thereof; tone determination means for determining the tone of the virtual object image based on detection results from the tone detection means and the type of the virtual object image to be superimposed and displayed or the purpose of the display thereof; virtual space image generation means for generating the virtual space image composed of the virtual object image based on the determination results from the tone determination means; and presentation means for presenting the virtual space image generated by the virtual space image generation means to the observer by superimposing the virtual space image on the physical space or the image thereof.
According to another aspect of the present invention, a control method of a mixed reality presentation apparatus for presenting a mixed reality to an observer by superimposing a virtual space image composed of a virtual object image on the physical space or an image thereof visually identified by the observer and presenting the virtual space image to the observer is provided, wherein the method includes: a tone detection step of detecting the tone of a predetermined region in the physical space or the image thereof; a tone determination step of determining the tone of the virtual object image based on the detection results from the tone detection step and the type of the virtual object image to be superimposed and displayed or the purpose of the display thereof; a virtual space image generation step of generating the virtual space image composed of the virtual object image based on the determination results from the tone determination step; and a presentation step of presenting the virtual space image generated by the virtual space image generation step to the observer by superimposing the virtual space image on the physical space or the image thereof.
According to still another aspect of the present invention, a computer-readable storage medium storing a control program for a mixed reality presentation apparatus for presenting a mixed reality to an observer by superimposing a virtual space image composed of a virtual object image on the physical space or an image thereof visually identified by the observer and presenting the virtual space image to the observer is provided, wherein the program includes: a tone detection process program for detecting the tone of a predetermined region in the physical space or the image thereof; a tone determination process program for determining the tone of the virtual object image based on the detection results from the tone detection process program and the type of the virtual object image to be superimposed and displayed or the purpose of the display thereof; a virtual space image generation process program for generating the virtual space image composed of the virtual object image based on the determination results from the tone determination process program; and a presentation process program for presenting the virtual space image generated by the virtual space image generation process program to the observer by superimposing the virtual space image on the physical space or the image thereof.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.